AC signal transmission device and AC device

Abstract

The present invention relates to an AC signal transmission device and an AC device, according to the present invention, in a device for transmitting AC power using resonance between resonators, it is possible to maintain high efficiency even if the positional relationship between resonators constituting a resonator pair changes. An AC signal transmission device according to the present invention comprises: a transmission line; a plurality of first phase shift circuits connected to the transmission line at a branch point; a plurality of resonator pairs respectively connected to the plurality of first phase shift circuits and including a power transmission coil and a power reception coil; and a plurality of second phase shift circuits connected to the plurality of resonator pairs, respectively, the plurality of second phase shift circuits being connected to each other at junction points, the AC device comprising: a transmission line; a plurality of phase shift circuits connected to the transmission line at branch points; and resonators connected to the plurality of phase shift circuits, respectively.

Description

Technical Field

[0001] The present disclosure relates to an AC signal transmission device and an AC device. Background Art

[0002] As electric vehicles and portable devices become more popular, there is an increasing demand for contactless power supply devices that transmit AC power contactlessly.

[0003] Although various methods of contactless power supply have been proposed, power supply using magnetic field resonance, which is lighter than electromagnetic induction and has a longer power transmission distance, has attracted attention (for example, non-patent document 1). The contactless power supply method described in non-patent document 1 supplies power through magnetic field resonance between resonators, so the requirements for the distance between coils and the accuracy of position alignment are more relaxed. In addition, since the device does not use magnets, the device can be lightweight.

[0004] By increasing the Q value of the coil used in the contactless power supply device, power can be efficiently transmitted even if the coupling coefficient is low (for example, non-patent document 2). In the contactless power supply method of non-patent document 2, if the coupling coefficient k changes due to changes in the distance between the resonators, the transmission characteristics will change significantly, so it is necessary to adjust as the transmission characteristics change.

[0005] According to microwave filter theory, if the external Q of the resonator is set according to the coupling coefficient k, transmission without reflection is possible (for example, Non-Patent Document 3).

[0006] The external Q can be set by dividing a capacitor used in a resonator and adjusting the capacitance value of each divided capacitor (for example, Patent Document 1).

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent No. 7039087

[0010] Patent Document 2: Japanese Patent No. 6729919

[0011] Patent Document 3: Japanese Patent No. 4835334

[0012] Patent Document 4: Japanese Patent No. 7261517

[0013] Non-patent literature

[0014] Non-patent literature 1: Wireless Power Transfer via Strongly Coupled Magnetic Resonances, Andre Kurs et al, Science Vol. 317, July 6, 2007

[0015] Non-patent document 2: T. Ohira "Angular expression of maximum power transfer efficiency in reciprocal two-port systems" Published in 2014IEEE WirelessPower Transfer Conference, May 8-9 2014, INSPEC Accession Number: 14395324

[0016] Non-patent document 3: I. Awai and T. Ishizaki "Superiority of BPF theory for design of coupled resonator WPT systems" Asia-Pacific Microwave Conference 2011, pp. 1889-1892 (2011) INSPEC Accession Number: 12656013

[0017] Non-patent document 4: SYRHui, W.Zhong and CKLee "ACritical Review of RecentProgress in Mid-Range Wireless Power Transfer" IEEE Transactions on PowerElectronics, vol.29, no.9, pp.4500-4511, Sept.2014

[0018] Non-patent document 5: Takehiro Imura, “Wireless power transmission using magnetic field resonance”, Mori Kita Publishing, 2017, p. 326-328 Summary of the invention

[0019] Problem that the invention aims to solve

[0020] In the contactless power supply that supplies power through magnetic field resonance between resonators, when the coupling coefficient k changes due to changes in the distance between the resonators, the transmission characteristics will change significantly. Therefore, it is necessary to change the external Q value by changing the impedance of the power supply or load connected to the resonator and the value of the capacitor in accordance with the change in the coupling coefficient k. For most contactless power supplies, it is difficult to avoid the situation that the positional relationship between the power transmission side coil and the power receiving side coil changes. That is, every time power is transmitted, because the value of the coupling coefficient k is not constant and the transmission characteristics change, it is necessary to change the circuit parameters such as the capacitance value.

[0021] The change of circuit parameters needs to be accompanied by the replacement or switching of components, so the mechanism becomes complicated and requires additional control. Therefore, a method of restoring the coupling coefficient k by mechanical methods when the positional relationship changes has also been proposed (for example, Patent Document 2). However, the method of Patent Document 2 cannot be responded to instantly because it requires mechanical action.

[0022] Therefore, it is desired to maintain high efficiency even if the positional relationship between the resonators constituting the resonator pair is changed.

[0023] An object of the present invention is to provide a power transmission system and device that can maintain high efficiency even if the positional relationship between resonators constituting a resonator pair changes.

[0024] Solutions to the problem

[0025] An AC signal transmission device in one embodiment of the present disclosure includes: a transmission line; a plurality of first phase-shifting circuits connected to the transmission line at branch points; a plurality of resonator pairs respectively connected to the plurality of first phase-shifting circuits; and a plurality of second phase-shifting circuits respectively connected to the plurality of resonator pairs, the plurality of second phase-shifting circuits being connected to each other at junction points.

[0026] Effects of the Invention

[0027] According to the AC signal transmission device and the AC device disclosed herein, even if the positional relationship between resonators changes, high-efficiency power transmission can still be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a diagram showing a series resonant circuit.

[0029] Figure 2 is a diagram showing a parallel resonant circuit.

[0030] Figure 3 This is a schematic diagram of a resonant power transmission circuit.

[0031] Figure 4 It is a diagram showing an SS type resonant power transmission circuit.

[0032] Figure 5 It is a graph showing the reflection characteristic and the transmission characteristic of the SS type resonant power transmission circuit.

[0033] Figure 6 The complex reflectance and transmittance of the SS type resonant power transmission circuit are plotted on a Smith chart.

[0034] Figure 7 This is a circuit diagram of a wireless power transmission device using a plurality of resonator pairs.

[0035] Figure 8 It is a diagram showing the arrangement of resonator coils in a multi-resonator structure.

[0036] Fig. 9 This is a graph showing the reflectivity in the multi-resonator structure on a Smith chart.

[0037] Fig.10 1 is a diagram showing transmittance and reflectance in the case of a circuit using a multi-resonator structure using two single-resonator structures that achieve the flattest matching when k=0.1.

[0038] Fig.11 The diagram shows transmission characteristics and reflection characteristics when the phase shift angle on the power transmission side is fixed at 20° and the phase shift angle on the power reception side is changed.

[0039] Fig.12 The graphs show the reflection characteristics and transmission characteristics in four different circuit structures.

[0040] Fig.13A This is a diagram showing a circuit using an SS type resonant power transmission circuit in which a resistor is connected to a zero-ohm power supply.

[0041] Fig. 13B This is a diagram showing a circuit using an SS type resonant power transmission circuit in which a capacitor is connected to a zero-ohm power supply.

[0042] Fig. 13C This is a diagram showing a circuit using an SS type resonant power transmission circuit in which an inductor is connected to a zero-ohm power supply.

[0043] Fig.13D This is a diagram showing a circuit using an SS type resonant power transmission circuit in which an impedance line is connected to a zero-ohm power supply.

[0044] Fig.14 This is a diagram showing the output power of a power source and the power consumption of a load when an SS type resonant power transmission circuit is used.

[0045] Fig.15This is a diagram showing the output power of a power source and the power consumption of a load when an SP type resonant power transmission circuit is used.

[0046] Fig.16 This is a diagram showing the output power of a power source and the power consumption of a load when a PS type resonant power transmission circuit is used.

[0047] Fig.17 This is a diagram showing the output power of a power source and the power consumption of a load when a PP type resonant power transmission circuit is used.

[0048] Fig.18 It is a diagram showing an example of a phase shift circuit composed of an LC circuit.

[0049] Fig.19 FIG. 1 is a diagram showing an example of a multi-resonator structure using a split-ring resonator.

[0050] Fig. 20 This is a diagram showing transmittance and reflectance when transmission is performed using a split ring resonator.

[0051] Fig.21 1 is a diagram showing the influence of the power supply side line length on the power transmission power of a single resonator structure.

[0052] Fig. 22 1 is a diagram showing the influence of the power supply side line length on the power transmission of the multi-resonator structure.

[0053] Fig.23 It is a diagram showing the reflection characteristics and transmission characteristics of a multi-line structure.

[0054] Description of Reference Numerals

[0055] 110, 210 load or power supply

[0056] 120, 220, 320, 350, 411, 422 capacitors

[0057] 130, 230 coils

[0058] 330, 413, 713, 733 power transmission coil

[0059] 340, 423, 723, 743 receiving coil

[0060] 310 AC power supply

[0061] 360, 1320 load

[0062] 410, 420 terminals

[0063] 701 Input terminal

[0064] 702, 752, 1916, 1926 branch points

[0065] 700 Resonance Power Transmission Circuit

[0066] 751 Output Terminals

[0067] 810, 820 Resonator coil substrate

[0068] 830 Rotation axis of resonator coil substrate

[0069] 1310 Zero Ohm Power Supply

[0070] 1330 Resistor

[0071] 1331 Capacitor

[0072] 1332 Inductor

[0073] 1333 Impedance Line

[0074] 1911, 1912, 1921, 1922 open-ring resonators

[0075] 1913 Input Line

[0076] 1914, 1915 Microstrip lines for input side phase shift circuits

[0077] 1923 output lines

[0078] 1924, 1925 Microstrip lines become phase shift circuits on the output side DETAILED DESCRIPTION

[0079] Figure 1 1 is a diagram showing a series resonant circuit. The series resonant circuit is a circuit in which a load or power source 110 is connected to a capacitor 120 and a coil 130 which are connected in series.

[0080] Figure 2 2 is a diagram showing a parallel resonant circuit. A parallel resonant circuit is a circuit in which a load or power source 210 is connected to a capacitor 220 and a coil 230 connected in parallel.

[0081] Figure 3 Schematic diagram of a resonant power transmission circuit. The resonant power transmission circuit includes an AC power source (power source) 310, a power transmission side resonant capacitor 320, a power transmission side resonant coil (power transmission coil) 330, a power reception side resonant coil (power reception coil) 340, a power reception side resonant capacitor 350, and a load 360.

[0082] exist Figure 3In the embodiment of the present invention, the transmission-side resonant capacitor 320 and the transmission-side resonant coil 330 are connected in series, so the transmission-side circuit is called a "series connection type (series (Series) type, S type)". In addition, the reception-side resonant capacitor 350 and the reception-side resonant coil 340 are connected in series, so the reception-side circuit is also an S type. The resonant power transmission circuit in which the transmission-side circuit is an S type and the reception-side circuit is an S type is called an "SS type resonant power transmission circuit".

[0083] As long as there is electromagnetic coupling between coils, electric power can be transmitted. Therefore, in addition to series-connected resonators, parallel-connected resonators can also be used to transmit electric power.

[0084] That is, in addition to the SS type resonant power transmission circuit, an SP type resonant power transmission circuit in which a power transmission side circuit is an S type and a power receiving side circuit is a parallel connection type (parallel type, P type), a PS type resonant power transmission circuit in which a power transmission side circuit is a P type and a power receiving side circuit is an S type, and a PP type resonant power transmission circuit in which a power transmission side circuit is a P type and a power receiving side circuit is a P type can also be used for power transmission.

[0085] Generally speaking, assuming that the inductance of the coil is L0 and the capacitance value of the capacitor is C0, the resonant frequency f0 of the resonator is given by the following equation (1).

[0086] [Formula 1]

[0087]

[0088] In order to perform resonant power transmission, the resonant frequency must be the same between the power transmission side of the resonator and the power reception side of the resonator. Here, the characteristic impedance of the resonator is called "resonator impedance", which is represented by Z K represents the resonator impedance and is defined as follows.

[0089] [Formula 2]

[0090]

[0091] Here, if the characteristic impedance of the signal line connected to the resonator, the power supply connected to the signal line, or the external circuit such as the load is Z S , then the external Q is Q e The definition of is as follows.

[0092] [Formula 3]

[0093] The case of a series resonator

[0094] Parallel resonator case

[0095] According to Non-Patent Document 3, if the coupling coefficient k and the external Q of the resonator on the power transmission side, i.e., Q eT and the external Q of the power receiving side resonator, i.e., Q eR If the relationship expressed by the following equation is satisfied, power can be transmitted without reflection between the power transmitting resonator and the power receiving resonator. This is called "median value matching".

[0096] [Formula 4]

[0097]

[0098] Furthermore, according to Non-Patent Document 3, if the relationship represented by the following equation is satisfied, “flattest matching” is achieved in which the frequency range of high efficiency is expanded to the entire region between the resonance frequencies.

[0099] [Formula 5]

[0100]

[0101] In wireless power transmission, a single frequency is usually used for the power transmission signal, so it is not necessary to achieve high efficiency over a wide bandwidth. It is sufficient to optimize only the resonant frequency of the resonator, so the condition of the loose equation (4) only needs to be satisfied.

[0102] However, according to non-patent document 3, when the coupling coefficient k is the same, if the flattest match of equation (5) is satisfied, the loss caused by the internal resistance of the coil, etc. can be minimized. In addition, if the flattest match is achieved, the frequency band with high efficiency is wider, so there is an advantage that a margin is left for circuit errors generated when manufacturing the resonator and the peripheral circuits.

[0103] Therefore, it is considered effective to use a condition as close as possible to equation (5). In the following description, the case where the flattest matching of equation (5) is satisfied is described, but as described above, in wireless power transmission, the condition of equation (4) may also be satisfied.

[0104] When equation (4) is combined with equation (3a) or (3b), the coupling that does not cause reflection is expressed by the following equation for each resonant power transmission circuit. ST is the output impedance of the power supply on the transmission side, Z SR is the input impedance of the load on the receiving side, Z KT is the resonator impedance of the power transmission side resonator, Z KR is the resonator impedance of the power receiving side resonator.

[0105] [Formula 6]

[0106]

[0107] These equations show that the output impedance Z of the power supply on the transmission side is ST After coupling through the resonator, the input impedance of the load on the receiving side becomes Z SR , that is, the resonant power transmission circuit has a function of an impedance converter that changes according to the coupling coefficient k.

[0108] Although the following description takes the SS type resonant power transmission circuit as an example, the same is true even in other forms as long as the impedance conversion of any one of the equations (6b) to (6d) corresponding to the form is used.

[0109] Figure 4 Here, if the resonator is composed of the power transmission coil 413 and the power receiving coil 423, both of which have a resistance of 1.591 μH, and the capacitor 412 and the capacitor 422, both of which have a resistance of 159.1 pF, the resonant frequency of the resonator is 10 MHz, and the characteristic impedance Z of the resonator is K The power transmission coil 413 and the power reception coil 423 of 1.591 μH can be formed by a coil of a conductive wire with a diameter of about 40 cm.

[0110] When the distance between the power transmission coil 413 and the power reception coil 423 is about the same length as the diameter, the coupling coefficient k is about 0.05. The coupling coefficient k decreases roughly inversely proportional to the cube of the distance. Although the range of the coupling coefficient k is determined according to the application, in this embodiment, it is assumed that the coupling coefficient k is about 0.01 to 0.5.

[0111] The output impedance of a line connected to the terminal 410 of the power transmission-side resonator, for example, a power supply, is Z T , the input impedance of the line connected to the terminal 420 of the power receiving side resonator is set to Z R Here, if Z T =10Ω, Z R =10Ω, then the characteristic impedance of the resonator is Z K =100Ω, therefore, according to equation (3a), the external Q on the power transmission side is Q eT = 10, the external Q on the receiving side is Q eR is also 10. Therefore, when k=0.1, equation (5) holds true, and the flattest matching can be achieved.

[0112] Figure 5 This is a graph showing the reflection characteristics and transmission characteristics of the SS type resonant power transmission circuit when the coupling coefficient k changes for a 10 MHz signal. Figure 5 In FIG. 1 , the dotted line represents the reflection characteristic (reflectivity), and the solid line represents the transmission characteristic (transmittance).

[0113] Figure 6 This is a graph showing the complex reflectance and transmittance of the SS type resonant power transmission circuit on a Smith chart. Figure 6 In the figure, the reflectivity of the SS type resonant power transmission circuit is represented by white circles and black circles, and the transmittance is represented by white diamonds and black diamonds.

[0114] If the coupling coefficient k changes, the reflectivity of the SS type resonant power transmission circuit moves from -1 to 1 on the real axis, and passes through the origin where the reflection is zero when k = 0.1. On the other hand, the transmittance is delayed by 270°, that is, it moves in the positive region on the imaginary axis, moves upward from the vicinity of the origin, and reaches the periphery and returns when k = 0.1.

[0115] As mentioned above, both series resonators and parallel resonators can be used as resonators on the power transmission side and the power receiving side. As shown in equations (6a) to (6d), when the resonator impedance and coupling coefficient are fixed, the combination of the optimal power supply impedance and the optimal load impedance that makes the reflection zero will change depending on the combination of the resonator form. By applying a resonator in a form whose optimal impedance value is close to the impedance of the power supply actually used and the resistance of the load, a circuit with less loss can be constructed.

[0116] Therefore, in addition to the SS type resonant power transmission circuit, studies are also being conducted on SP type, PS type, and PP type resonant power transmission circuits.

[0117] The coupling coefficient k is determined by the distance between the coils that constitute the resonator. Therefore, whether a series resonator or a parallel resonator is used, the coupling coefficient k does not change. In addition, if the resonant frequency and the coil are the same, the resonator impedance is the same value. In order to achieve the flattest matching, equation (5) needs to be satisfied. Therefore, for example, when k = 0.1, for the power transmission side, regardless of the resonator form, Q eT =10.

[0118] The characteristic impedance Z of the resonator K When the series resonator is used, the characteristic impedance Z of the signal source is calculated according to equation (3a). T When the parallel resonator is used, the characteristic impedance Z of the signal source is set to 10Ω according to equation (3b). T By setting the impedance to 1000Ω, power can be transmitted while satisfying the most flat matching. The same is true for the load impedance on the power receiving side.

[0119] Regardless of the corresponding object, if the resonator is a series type, when k is small, the reflectivity is near -1 on the real axis of the Smith chart. If k increases, the reflectivity passes through the origin at k = 0.1 and moves to the +1 side. In the case of a parallel type resonator, when k is small, the reflectivity is at +1. As k increases, the reflectivity passes through the origin at k = 0.1 and moves to -1.

[0120] In the case of SS type, Figure 6 As shown in the figure, the phase delay is always 270 degrees (positive direction on the imaginary axis), and the transmittance is near the origin when k is small. When k = 0.1, the transmittance reaches the periphery at the transmittance of 1. If it is greater than 1, the transmittance returns to the origin again. The SP type and SS type make the same changes when the phase delay is 0 degrees (positive direction on the real axis). The PP type makes the same changes when the phase delay is 90 degrees (negative direction on the imaginary axis).

[0121] If the phase is included, it will change as described above, but no matter which form, the absolute value of the change in reflectivity and transmittance is the same as Figure 5 The SS type is roughly the same.

[0122] (Multi-resonator structure)

[0123] Figure 7 The circuit diagram of the wireless power transmission device using multiple resonator pairs is shown in FIG. Two SS type resonant power transmission circuits are connected in parallel, and phase shift circuits are provided before and after each resonant power transmission circuit. Figure 7 The structure in which two resonator circuits are connected in parallel is called a "multi-resonator structure". Figure 3 Such a resonator circuit structure is called a "single resonator structure".

[0124] exist Figure 7 In FIG. 7 , a plurality of lines connected in parallel to input terminal 701 are connected at branch point 702. A line refers to a series of circuits connected in series. Figure 7 For convenience, the upper side of the lines is called "line 1" and the lower side is called "line 2". The capacitance of each capacitor constituting each resonator pair, that is, the capacitance C of capacitor 712 A 1. Capacitance C of capacitor 722 B 1. Capacitance C of capacitor 732 A 2. Capacitance C of capacitor 742 B 2, the inductance of each power transmission coil constituting each resonator pair, that is, the inductance L of the power transmission coil 713 A 1. Inductance L of the receiving coil 723 B 1. Inductance L of the power transmission coil 733 A 2. Inductance L of the receiving coil 743B 2 is also equal.

[0125] The input terminal 701 is connected to a branch point 702. The branch point 702 branches into a line 1 and a line 2. The line 1 includes a phase shift circuit 711, a resonator pair, and a phase shift circuit 721. The resonator pair includes a capacitor 712, a power transmission coil 713, a power reception coil 723, and a capacitor 722.

[0126] One end of the phase shift circuit 711 is connected to the branch point 702. The other end of the phase shift circuit 711 is connected to one end of the capacitor 712. The other end of the capacitor 712 is connected to one end of the power transmission coil 713. The other end of the power transmission coil 713 is grounded (connected to the ground). The power transmission coil 713 and the power reception coil 723 are coupled with a coupling coefficient k1.

[0127] One end of the power receiving coil 723 is grounded. The other end of the power receiving coil 723 is connected to one end of the capacitor 722. The other end of the capacitor 722 is connected to one end of the phase shift circuit 721. The other end of the phase shift circuit 721 is connected to a branch point (junction point) 752. The branch point 752 is connected to the output terminal 751.

[0128] The line 2 includes a phase shift circuit 731 , a resonator pair, and a phase shift circuit 741 . The resonator pair includes a capacitor 732 , a power transmission coil 733 , a power reception coil 743 , and a capacitor 742 .

[0129] One end of the phase shift circuit 731 is connected to the branch point 702. The other end of the phase shift circuit 731 is connected to one end of the capacitor 732. The other end of the capacitor 732 is connected to one end of the power transmission coil 733. The other end of the power transmission coil 733 is grounded (connected to the ground). The power transmission coil 733 and the power receiving coil 743 are coupled with a coupling coefficient k2.

[0130] One end of the power receiving coil 743 is grounded. The other end of the power receiving coil 743 is connected to one end of the capacitor 742. The other end of the capacitor 742 is connected to one end of the phase shift circuit 741. The other end of the phase shift circuit 741 is connected to the branch point 752.

[0131] The input and output of each phase shift circuit are symmetrical, and the input impedance and output impedance have the same impedance value. Therefore, the phase shift circuit is a circuit that produces the same phase delay for signals input from either side.

[0132] (Structure of coil with multi-resonator structure)

[0133] In a resonant power transmission device, the electrical effect of changes in the positional relationship between the power transmission and power reception coils is manifested as changes in the coupling coefficient. In other words, the coupling coefficient changes depending on the distance between the power transmission coil and the power reception coil, the relative orientation of the power transmission coil and the power reception coil, etc. In a multi-resonator structure, by making efforts in the configuration of the coils, the two coupling coefficients can be changed to the same value.

[0134] Figure 8 Yes means Figure 7 FIG. 8 is a diagram showing the arrangement of resonator coils in a multi-resonator structure. On the substrate 810 on the power transmission side, the power transmission coil 713 and the power transmission coil 733 are arranged. On the substrate 820 on the power reception side, the power reception coil 723 and the power reception coil 743 are arranged. The power transmission coil 713, the power transmission coil 733, the power reception coil 723, and the power reception coil 743 have the same structure and the same characteristics.

[0135] The power transmission coil 713 and the power reception coil 723 are coils of the resonator of line 1, and the power transmission coil 733 and the power reception coil 743 are coils of the resonator of line 2. The substrates 810 and 820 are arranged in parallel, and when these substrates are arranged at a reference position, the power transmission coil 713 and the power reception coil 723 are arranged to face each other, and the power transmission coil 733 and the power reception coil 743 are arranged to face each other.

[0136] If it is assumed that power is transmitted from the ground side to the vehicle side, the ground side, i.e., the power transmission side, is fixed, so the substrate 810 is fixed, and the vehicle side, i.e., the power receiving side, is movable as a whole. When the vehicle is parked on a flat road, although the substrate 810 is parallel to the substrate 820, due to the parking position or orientation of the vehicle and the difference in the vehicle, the substrate 820 may move in parallel in the x and y directions relative to the reference position depending on the parking position of the vehicle, and may rotate around an axis perpendicular to the substrate depending on the parking direction of the vehicle. However, as long as the parking direction of the vehicle is set to a certain direction, relative to the accurate opposite configuration, although the substrate 820 will move in parallel in the state where the orientation is fixed to the x, y, and z directions, it will not rotate.

[0137] The power transmitting coil 713 and the power transmitting coil 733 are arranged on the substrate 810, and the power receiving coil 723 and the power receiving coil 743 are arranged on the substrate 820. Therefore, with respect to the movement of the substrates 810 and 820 in the x, y, and z directions in a state where the orientations are fixed, the distance between the power transmitting coil 713 and the power receiving coil 723, and the distance between the power transmitting coil 733 and the power receiving coil 743 will remain the same.

[0138] That is, the coupling coefficient k1 between the power transmission coil 713 and the power reception coil 723 and the coupling coefficient k2 between the power transmission coil 733 and the power reception coil 743 are the same value (k1=k2) although they change. That is, when the stopping position of the vehicle is shifted in the front-back and left-right directions and the coupling state has changed, as long as the orientation of the vehicle is kept constant, the coupling coefficients of the two resonator pairs are always the same value.

[0139] In addition, when the vehicle height changes due to a change in vehicle weight, thereby causing a change in the coupling state, although the distance between the substrates 810 and 820 in the z direction changes, the distance between the power transmitting coil 713 and the power receiving coil 723 and the distance between the power transmitting coil 733 and the power receiving coil 743 are the same, and although the coupling coefficient changes, the value is the same.

[0140] In addition, there is a case where the substrate 810 and the substrate 820 rotate about the same rotation axis 830 and the coupling state changes. As long as the position of the rotation axis is set at a point equidistant from the two coils, even when the substrate 810 and the substrate 820 rotate about the rotation axis 830, the distance between the power transmission coil 713 and the power reception coil 723, and the distance between the power transmission coil 733 and the power reception coil 743 remain the same. That is, the coupling coefficient k1 between the power transmission coil 713 and the power reception coil 723, and the coupling coefficient k2 between the power transmission coil 733 and the power reception coil 743 change, but are the same value (k1=k2).

[0141] so, Figure 7 In the resonator coupling circuit, the inductance of each coil is the same, and the capacitance is the same. Although the coupling coefficient of each resonator varies, its value is the same.

[0142] This relationship can be achieved even in a multi-resonator structure that is more complex due to the use of mechanical linkages or cam mechanisms.

[0143] Furthermore, the manner in which the coupling coefficient between coils changes varies depending on the shape of the coils. Therefore, if the shapes of the coils are different, the design becomes complicated, so it is ideal that the shapes of the coils are the same.

[0144] If you will Figure 7 The characteristic impedance of each line between the branch point 702 and the branch point 752 is set to 10Ω, then the input impedance Z at the input terminal 701 matched at the branch point 702 is T0 , and the output impedance Z at the output terminal 751 matched at the branch point 752 R0The characteristic impedance of each line is 1 / 2, that is, 5Ω. In order to avoid confusion, the line impedance is expressed as the value of each single line in the multi-line state. That is, unless otherwise specified, the characteristic impedance before a line is branched into two lines or after two lines are combined into one line is 1 / 2 of the line impedance. As a result, the impedance matching at the branch points 702 and 752 is guaranteed.

[0145] Fig. 9 is a graph showing the reflectivity in the multi-resonator structure on the Smith chart. Here, the reference impedance is set to 10Ω. Figure 7 For the circuit, the case where the phase shift angles of the four phase shift circuits are all 0° is the same as the case where there is no phase shift circuit. Therefore, it is equivalent to connecting two phase shift circuits in parallel. Figure 4 That is, the k-value dependence of the reflectivity on the line 1 side and the line 2 side viewed from the branch point 702 is also similar to Figure 5 and Figure 6 same.

[0146] When k=0.1, the reflectivity is zero, and therefore the reflectivity is at the origin 901. That is, both the line 1 and the line 2 transmit signals from the input terminal 701 to the output terminal 751 without reflection.

[0147] Next, a case where k=0.013 due to a change in the positional relationship of the resonators will be described.

[0148] Figure 7 This is an SS type resonant power transmission circuit with series resonators on both the power transmission side and the power receiving side. The characteristic impedance of the resonator is Z K is 100Ω. Therefore, if equations (3a) and (5) are considered, the output impedance Z of the power supply on the transmission side is ST And the input impedance Z of the load on the receiving side SR Both are 1.3Ω(Z TO , Z SO Half of it), the flattest match is established.

[0149] If the input impedance of the load on the receiving side is Z SR The impedance of the resonator is set to 1.3Ω, which is the flattest matching. The output impedance of the power supply on the power transmission side is kept at 10Ω. The reflectivity of the resonator seen from the power transmission side is (-0.77, 0). Fig. 9 Point 902.

[0150] Therefore, the phase shift angle of the phase shift circuit 711 is changed. If the characteristic impedance of the phase shift circuit is set to 10Ω, which is the same as the reference impedance, the reflection coefficient moves on a circle 910 centered on the origin.

[0151] Next, if the phase shift angle changes by ±40° on the circle 910, it intersects the 10Ω isoconductivity circle 911 at two points 903 and 904. The real part of the impedance shown at points 903 and 904 is 10Ω, and the absolute value of the imaginary part is the same but the positive and negative signs are opposite.

[0152] That is, if the phase shift angle of the phase shift circuit 711 and the phase shift angle of the phase shift circuit 731 are adjusted and set in the above manner Figure 7 In the circuit, the real part of the composite impedance of the two lines viewed from the branch point 702 is 5Ω, and the imaginary part is 0. Therefore, even if the two lines are branched at the branch point 702, impedance matching still holds, and therefore, no reflection occurs at the branch point 702.

[0153] Furthermore, since the delay in the phase shift circuit takes only positive values, changing the phase shift angle by ±X° means performing a phase shift of +X° (arrow 912 ) and a phase shift of (360−X)° (arrow 913 ).

[0154] As for the reflected wave, since it passes through the phase shift circuit twice, the change in the phase shift angle of the phase shift circuit can be half of +X°, that is, +X / 2° and (180-(X / 2))°. Figure 7 In the case of , the phase shift angle of the phase shift circuit 711 is Δ°, and the phase shift angle of the phase shift circuit 731 is (180-Δ)°, where Δ is 20.

[0155] Here, it is assumed that the impedance of the receiving side line is already 1.3Ω. However, because the impedance at the branch point 752 is actually 10Ω, the receiving side also uses the same method to perform the same settings as the transmitting side so that it looks like a line with a characteristic impedance of 1.3Ω is connected. That is, the phase shift angle of the phase shift circuit 721 is set to (180-Δ)°, and the phase shift angle of the phase shift circuit 741 is set to Δ°, where Δ is 20. Although two phase shift angles are assigned to line 1 and line 2, at this time, they are selected in a way that the total phase delay on the transmitting side and the receiving side in line 1 and line 2 becomes the same value.

[0156] Fig.10 This is a graph showing the transmittance and reflectance of a circuit using a multi-resonator structure using two single resonator structures that achieve the flattest match when k = 0.1. Line 1001 shows the transmittance when Δ = 20, line 1003 shows the transmittance when Δ = 40, line 1005 shows the transmittance when Δ = 60, line 1002 shows the reflectance when Δ = 20, line 1004 shows the reflectance when Δ = 40, and line 1006 shows the reflectance when Δ = 60. There is no reflection when k = 0.1, and the other values ​​of k that achieve no reflection are 0.013, 0.069, and 0.3, respectively.

[0157] In addition, although Fig.10 In FIG. 1 , the phase shift amounts on the power transmission side and the power reception side are assumed to be the same, but the phase shift amounts on the power transmission side and the power reception side do not necessarily need to be the same.

[0158] Fig.11 The diagram shows transmission characteristics and reflection characteristics when the phase shift angle of the phase shift circuit on the power transmission side is fixed at 20° and the phase shift angle of the phase shift circuit on the power reception side is changed.

[0159] Since the receiving side of line 1001 and line 1002 is also set to Δ = 20, Fig.10 Line 1103 represents the transmission characteristics when Δ=40 on the receiving side, line 1105 represents the transmission characteristics when Δ=60 on the receiving side, line 1104 represents the reflection characteristics when Δ=40 on the receiving side, and line 1106 represents the reflection characteristics when Δ=60 on the receiving side.

[0160] Regarding lines 1103 to 1106, although there is no peak but reflection at k=0.1 set according to the external Q of the individual lines, impedance matching is established at the other two k values, and the transmittance still has a peak in a manner that makes the reflectivity 0 at the two k values.

[0161] Although the transmittance peaks are separated into two places when the two k values ​​of impedance matching are greatly different, if the k values ​​are made close to each other, the efficiency can be roughly constant between the peaks. In addition, the two k values ​​can also be made consistent. Even when the two k values ​​are made consistent, the flatness of the efficiency near the peak increases compared to the case of a single resonator structure, and the range of high efficiency increases.

[0162] The above describes the SS type resonant power transmission circuit, but the same is true for the SP type resonant power transmission circuit, the PS type resonant power transmission circuit, and the PP type resonant power transmission circuit. When the type is changed, it is sufficient to pay attention to the difference between equation (3a) and equation (3b), and the difference in the phase delay of the resonator itself.

[0163] Table 1 shows the signal source impedance and the phase shift angle of the phase shift circuit taking these differences into consideration.

[0164] [Table 1]

[0165]

[0166] In Table 1, Δ T is the phase shift angle of the phase shift circuit on the power transmission side, Δ R is the phase shift angle of the phase shift circuit on the receiving side, Z Kis the resonator impedance, k0 is the set k value (0.1 in the embodiment). T Each other and Δ R By setting the values ​​to be the same, almost the same reflection characteristics and transmission characteristics can be obtained regardless of the circuit form.

[0167] Fig.12 The graphs show the reflection characteristics and transmission characteristics in four different circuit structures. Fig.12 In order to make all external Qs 10, the impedance of the power supply or load is set to 1000Ω when a parallel resonator is used, the impedance of the power supply or load is set to 10Ω when a series resonator is used, and the phase shift angle is set to Δ T =20° and Δ R =60° and the settings shown in Table 1 are performed.

[0168] Line 1214 represents the transmission characteristics, and in any of the SS type resonant power transmission circuit, SP type resonant power transmission circuit, PS type resonant power transmission circuit, and PP type resonant power transmission circuit, the transmission characteristics are almost the same. Fig.12 In FIG. 1 , line 1106 represents the reflection characteristic of the SS type resonant power transmission circuit, line 1211 represents the reflection characteristic of the PP type resonant power transmission circuit, line 1212 represents the reflection characteristic of the PS type resonant power transmission circuit, and line 1213 represents the reflection characteristic of the SP type resonant power transmission circuit. Although there are slight differences, substantially the same characteristics can be obtained.

[0169] (Use of zero ohm power supply)

[0170] In the description so far, Figure 7 In the circuit of the multi-resonator structure shown, the output impedance of the AC power supply 310 connected to the input terminal 701 and the input impedance of the load 360 connected to the output terminal 751 are finite impedances. The purpose is to set the output impedance of the power supply and the input impedance of the cable, and the output impedance of the cable and the input impedance of the load to the same impedance, thereby eliminating reflections between the power supply and the cable, and between the cable and the load. The means of eliminating reflections can be said to be a common means in microwave circuits.

[0171] However, if the power supply has a finite output impedance, power consumption due to the impedance will occur inside the power supply. Therefore, although reflection in the resonator unit can be prevented, the power efficiency of the entire system will decrease (for example, Non-Patent Document 4).

[0172] In order to avoid power consumption in the power supply, a switching power supply is used, which is a power supply composed of a lossless switch and a lossless filter such as an LC circuit. The switching power supply is a voltage source whose output voltage does not change due to the load, so the output impedance is 0Ω, and it is called a "zero-ohm power supply."

[0173] In this embodiment, power transmission is performed, and since it is preferred that no power is consumed inside the power supply, a zero-ohm power supply is preferably used. On the other hand, if the output impedance of the power supply is set to 0Ω, there is a mismatch between the power supply and the line, and thus reflection occurs.

[0174] Therefore, the effect when a zero-ohm power supply in which impedance matching is not achieved is used in the connection portion with the power supply is verified.

[0175] Fig.13A This is a diagram showing a circuit in which a resistor is inserted in series with a zero-ohm power supply and an SS-type resonant power transmission circuit is used in a conventional finite resistance power supply circuit. Figure 7 circuit.

[0176] When the setting is made to achieve the flattest matching when k=0.1, the impedance on the power supply side and the impedance on the load side are 10 ohms. In addition, the phase shift angle in the phase shift circuit is set so that Δ T =20°, Δ R =Value when 60°.

[0177] The reflection characteristics when the following power supply is used are given by Fig.12 The line 1106 shows that the transmission characteristic is Fig.12 The line 1214 shows that the power supply has a finite output impedance that matches the input impedance of the resonator circuit. Referring to the line 1106 showing the reflection characteristic, it can be seen that the reflection becomes zero when k=0.035 and k=0.170.

[0178] Here, the power transmission is assumed and Fig.13A The AC power source 1310 is set to a zero-ohm power source with an effective output voltage of 100V, and the resistor 1330 is set to 5Ω.

[0179] Fig.14 This is a diagram showing the output power of the zero-ohm power supply 1310 and the power consumption of the load when the SS type resonant power transmission circuit is used.

[0180] In this case, Fig.12As shown, when k=0.035 and k=0.170, the impedance is matched, because the resistor 1330 and the resonant power transmission circuit 700 of the multi-resonator structure are connected in series, so the load from the zero-ohm power supply 1310 is 10Ω. The output effective voltage of the zero-ohm power supply 1310 is 100V, so the supplied power is (100V) 2 / 10Ω means 1000W.

[0181] exist Fig.14 In FIG. 1 , line 1410 represents the power consumed by load 1320 when a 5Ω resistor 1330 is inserted in series with the output of zero-ohm power supply 1310, and line 1420 represents the power output by zero-ohm power supply 1310 in this case. The difference between these two powers is the power consumed by resistor 1330. This power is the power loss in the power supply that has been impedance matched, and here, removing this power loss is the goal to be achieved.

[0182] When k=0.035 and 0.17, where the reflection is zero, of the output power of 1000 W of the zero-ohm power supply 1310 , 500 W is consumed by the resistor 1330 and 500 W is consumed by the load 1320 .

[0183] That is, the loss is 50%, or the efficiency is 50%. 50% efficiency can hardly be considered as high-efficiency power transmission.

[0184] In order to reduce the loss caused by the consumption in the resistor 1330, it is necessary to reduce the resistance value of the resistor 1330 connected in series to the zero-ohm power source 1310. If the resistance value of the resistor 1330 is 0Ω, the loss caused by the resistor 1330 will not occur.

[0185] If the resistance value of the resistor 1330 is reduced, the two k values ​​at which the power output by the zero-ohm power source 1310 reaches a peak value approach each other and converge to one when the resistance value becomes 0Ω. Fig.14 Line 1460 is the power output by the zero-ohm power supply 1310 when the resistor 1330 becomes 0Ω.

[0186] In this case, even if the voltage of the zero-ohm power supply 1310 is fixed, the power output by the zero-ohm power supply 1310 will also change significantly as the k value changes. That is, in order to keep the power supplied to the load 1320 constant, it is necessary to change the voltage supplied by the zero-ohm power supply 1310 according to the k value, which will generate additional work. In addition, the current value will also change, requiring additional capacity to be added to the power supply.

[0187] Fig. 13B Indicates that capacitor 1331 is connected to replace Fig.13A The resistor 1330 in the circuit. Fig. 13C Indicates that an inductor 1332 is connected to replace Fig.13A The resistor 1330 in the circuit. Fig.13D Indicates that the impedance line 1333 is connected instead of Fig.13A The circuit includes resistor 1330. Even if current flows through capacitor 1331, inductor 1332, and impedance line 1333, no loss occurs.

[0188] When the capacitor 1331 or the inductor 1332 is connected, the reactance value which is the imaginary part of the impedance is set to 5Ω, which is the same value as the resistance value of the resistor 1330 .

[0189] Specifically, when the capacitor 1331 is connected instead of the resistor 1330, a capacitor of 3.183 nF is connected. When the inductor 1332 is connected instead of the resistor 1330, an inductor of 79.6 nH is connected.

[0190] In addition, when the impedance line 1333 is connected instead of the resistor 1330, an impedance line having a characteristic impedance of 5Ω and a line length of 1 / 8 of the wavelength (a phase shift angle of 45°) is connected. Fig.13A The same is true when the resistor 1330 is set to 5Ω.

[0191] exist Fig.14 In the example, line 1430 indicates Fig. 13B The power consumed by the load 1320, line 1440 represents Fig. 13C The power consumed by the load 1320 shows exactly the same characteristics. Fig.14 In the figure, line 1450 indicates Fig.13D The power consumed by the load 1320.

[0192] In lines 1430 , 1440 , and 1450 , the peak values ​​of power consumption are at k=0.035 and k=0.17. The peak power in lines 1430 and 1440 is 1000W, and the peak power in line 1450 is 2000W.

[0193] Although the peak power values ​​are different, the peak values ​​of the power consumption of the load 1320 are both at k=0.035 and k=0.17. For k of 0.035<k<0.17, even if the k value fluctuates, the power consumed by the load 1320 does not change significantly. In these cases, the power consumption of the load is the same as the output power of the power supply, so there is no need for the zero-ohm power supply 1310 to generate a wide range of power.

[0194] In the above, the case where the SS type resonant power transmission circuit is used has been described, but the same is true for the SP type resonant power transmission circuit, the PS type resonant power transmission circuit, and the PP type resonant power transmission circuit.

[0195] First, similarly to the SS type resonant power transmission circuit, for any of the above types of resonant power transmission circuits, the impedance of the load is set so that the flattest matching is achieved when k = 0.1. In the case of a PS type resonant power transmission circuit in which the load side resonator is an S type, the impedance is set to 10Ω, and in the case of an SP type resonant power transmission circuit or a PP type resonant power transmission circuit in which the load side resonator is a P type, the impedance is set to 1000Ω.

[0196] exist Fig.13A , Fig. 13B , Fig. 13C , Fig.13D In the embodiment, the resonant power transmission circuit 700 is of SS type. Now, a description will be given of a case where this part is changed to a resonant power transmission circuit of an appropriate corresponding type.

[0197] In the case of the SP type resonant power transmission circuit, the resistor 1330 connected in series to the zero-ohm power supply 1310 in order to achieve impedance matching between the power supply and the resonant power transmission circuit is 5Ω. Therefore, as the capacitor 1331, the inductor 1332 or the impedance line 1333, the same capacitance, inductance or impedance as that of the SS type resonant power transmission circuit can be used.

[0198] On the other hand, in the case of a PS type resonant power transmission circuit or a PP type resonant power transmission circuit, the resistance value of the resistor 1330 connected in series to the zero ohm power supply 1310 for matching is 500Ω. Therefore, it is sufficient to set the capacitance of the capacitor 1331 to 31.83pF, the inductance of the inductor 1332 to 7960nH, the characteristic impedance of the impedance line 1333 to 500Ω, and the line length to 1 / 8 of the wavelength (phase shift angle is 45°).

[0199] Fig.15 This is a diagram showing the output power of a power source and the power consumption of a load when an SP type resonant power transmission circuit is used.

[0200] exist Fig.15 In FIG. 1 , line 1510 is the power consumed by load 1320 when a 5Ω resistor 1330 is inserted in series with the output of zero-ohm power supply 1310 in order to achieve impedance matching in the power supply unit, and line 1520 is the power output by the power supply in this case. The difference between these two powers becomes the power consumed by resistor 1330. Line 1560 is the power consumed by load 1320 when the resistance value of resistor 1330 becomes 0Ω.

[0201] Line 1530 is the case where the resistor 1330 is replaced by the capacitor 1331 Fig. 13B Line 1540 is the case where the resistor 1330 is replaced by the inductor 1332. Fig. 13CLine 1550 is the case where the resistor 1330 is changed into the impedance line 1333. Fig.13D The power consumed by the load 1320.

[0202] Fig.16 This is a diagram showing the output power of a power source and the power consumption of a load when a PS type resonant power transmission circuit is used.

[0203] exist Fig.16 In FIG. 1 , line 1610 is the power consumed by the load when a 500Ω resistor 1330 is inserted in series with the output of the zero-ohm power supply 1310 to achieve impedance matching in the power supply unit, and line 1620 is the power output by the power supply in this case. Line 1660 is the power consumed by the load 1320 when the resistance value of the resistor 1330 becomes 0Ω.

[0204] Line 1630 is the case where the resistor 1330 is replaced by the capacitor 1331 Fig. 13B Line 1640 is the case where the resistor 1330 is replaced by the inductor 1332. Fig. 13C Line 1650 is the case where the resistor 1330 is changed into the impedance line 1333. Fig.13D The power consumed by the load 1320.

[0205] Fig.17 This is a diagram showing the output power of a power source and the power consumption of a load when a PP type resonant power transmission circuit is used.

[0206] exist Fig.17 In FIG. 1 , line 1710 is the power consumed by the load when a 500Ω resistor 1330 is inserted in series with the output of the zero-ohm power supply 1310 to achieve impedance matching in the power supply unit, and line 1720 is the power output by the power supply in this case. Line 1760 is the power consumed by the load 1320 when the resistance value of the resistor 1330 becomes 0Ω.

[0207] Line 1730 is the case where the resistor 1330 is replaced by the capacitor 1331. Fig. 13B Line 1740 is the case where the resistor 1330 is replaced by the inductor 1332. Fig. 13C Line 1750 is the case where the resistor 1330 is changed into the impedance line 1333. Fig.13D The power consumed by the load 1320.

[0208] Reference Figure 15 to Figure 17It can be seen that the output power of the SP type resonant power transmission circuit is approximately the same as that of the SS type resonant power transmission circuit, and the output power of the PS type resonant power transmission circuit and the PP type resonant power transmission circuit is about 1 / 100 of that of the SS type resonant power transmission circuit. The reason for this is that in order to match the external Q with the k value, the input impedance to the resonator is set to 5Ω in the case of the S type, and the input impedance to the resonator is set to 500Ω in the case of the P type. On the other hand, in terms of the increase and decrease corresponding to the change in the k value, the peaks are all at k=0.035 and k=0.17, and there is little fluctuation between them. It can be judged that when a predetermined capacitor is provided in the power supply unit, a predetermined inductor is provided, or a predetermined impedance line is provided, since there is no loss caused by the power supply resistance, the power supplied from the power supply is all consumed by the load, and the power fluctuation caused by the change in the k value is suppressed.

[0209] according to Figure 15 to Figure 17 As with the SS type, by providing appropriate lossless components, substantially constant power can be transmitted without loss even when the coupling coefficient changes.

[0210] (Phase shift circuit composed of LC)

[0211] In the descriptions so far, the phase shift circuit has been analyzed using an impedance line for ease of simulation. However, when using a MHz frequency band, the impedance line is physically very long, so the phase shift circuit is generally composed of separate components such as capacitors and inductors.

[0212] Fig.18 It is a diagram showing an example of a phase shift circuit composed of an LC circuit.

[0213] Table 2 shows the capacitance C and inductance L used in the phase shift circuit of FIG. 13 when a 10 MHz signal is phase shifted by 10° to 90° when the characteristic impedance is 10Ω or 1000Ω. By providing the circuit with multiple stages, the phase shift can be handled by 90° or more.

[0214] [Table 2]

[0215]

[0216] (In the case of a split-ring resonator)

[0217] In the description so far, an LC resonator is used as a resonator, and electromagnetic coupling caused by mutual inductance between coils is used to transmit power. However, as the frequency increases, the LC resonator is difficult to cope with, so an open ring resonator is used (for example, Patent Document 3).

[0218] The open-ring resonator is a resonator formed by bending a half-wavelength antenna into a ring shape and bringing the two ends close together. By placing the open-ring resonators close together, electromagnetic coupling is used to transmit power contactlessly. The external Q of the open-ring resonator depends on the characteristic impedance of the line itself, the characteristic impedance of the input and output signal lines, and the position of the ring where the signal line is connected (Patent Document 4). The coupling coefficient is determined by the positional relationship, distance, and relative orientation of the notch between the two open-ring resonators.

[0219] Fig.19 1 is a diagram showing an example of a multi-resonator structure using open-ring resonators. Open-ring resonators 1911 and 1912 are formed on one printed circuit board, and open-ring resonators 1921 and 1922 are formed on another printed circuit board. Open-ring resonators 1911 and 1921, and open-ring resonators 1912 and 1922 are arranged facing each other in a close proximity, and output the power input from input line 1913 to output line 1923 in a non-contact manner.

[0220] exist Fig.19 In FIG. 1 , although the metal patterns on each surface are drawn in an offset manner for ease of understanding, the split ring resonators 1911 and 1921 and the split ring resonators 1912 and 1922 are arranged so as to overlap one another.

[0221] Therefore, when the substrates on which the split ring resonators are mounted are kept parallel and spaced apart, or are laterally offset, the relative positional relationship between the split ring resonators 1911 and 1921 and 1912 and 1922 is the same, and therefore the coupling coefficients in the two resonator groups are equal.

[0222] The split-ring resonators all use 1μm thick gold wiring, with an outer diameter of 15mm, a circumferential line width of 5mm, a resonant frequency of 2.45GHz, and are formed on a printed circuit board with a thickness of 1mm and a relative dielectric constant of 4.2. Microstrip lines 1914, 1915, 1924, and 1925 with a characteristic impedance of 100Ω are connected to the portion of each split-ring resonator at 90° from the midpoint of the ring.

[0223] Microstrip lines 1914 and 1915 from input line 1913 to each split-ring resonator mounting portion, and microstrip lines 1924 and 1925 from each split-ring mounting portion to output line 1923 form a phase shift circuit. The characteristic impedance of input line 1913 and output line 1923 is 50Ω.

[0224] The following will be Fig.19The structure in which two resonator pairs are connected in parallel as described is called a "multi-resonator structure", and the structure using one resonator pair is called a "single resonator structure". The characteristic impedance of the input and output lines of the single resonator structure is set to 100Ω, while the input line 1913 and the output line 1923 of the multi-resonator structure are connected in parallel with two resonator pairs, so matching is achieved by setting the characteristic impedance of the input line 1913 and the output line 1923 to 50Ω.

[0225] If the distance between the printed circuit boards constituting the open-ring resonators, i.e., the distance between the open-ring resonators, is changed, the coupling coefficient between the rings decreases as the distance between the open-ring resonators increases. On the other hand, since the connection point of the wiring to the open-ring resonator is fixed at a position 90° from the midpoint of the circumference of the ring, the value of the external Q is fixed.

[0226] Fig. 20 It is a graph showing the transmittance and reflectance when transmission is performed using the above-mentioned split ring resonator.

[0227] Line 2001 indicates the transmittance of a single resonator structure, and line 2002 indicates the reflectance. When the inter-ring distance is 4.5 mm, the flattest matching is achieved, the reflectance becomes zero, and the maximum transmittance is exhibited. Due to the loss caused by the skin effect of the gold wiring of the split ring resonator, the transmittance does not become 1. In the case of a single resonator structure, the transmittance reaches more than 90% within the range of about 1.5 mm between 3.5 mm and 5 mm of the inter-ring distance.

[0228] On the other hand, regarding the multi-resonator structure ( Fig.19 ), line 2003 represents the transmittance when the phase shift angle of microstrip line 1915 and microstrip line 1925 is set to 55°, and the phase shift angle of microstrip line 1914 and microstrip line 1924 is set to 125°, and line 2004 represents the reflectivity in this case.

[0229] As with the single resonator structure, reflection is suppressed when the inter-ring distance is 4.5 mm, and reflection is also suppressed when the inter-ring distance is 2.2 mm. Therefore, a transmittance of 90% is achieved within the range of 5.5 mm between 1 mm and 6.5 mm.

[0230] In addition, line 2005 represents the transmittance when the phase shift angles of microstrip line 1914 and microstrip line 1915 on the power transmitting side are not changed, the phase shift angle of microstrip line 1925 on the power receiving side is set to 35°, and the phase shift angle of microstrip line 1924 is set to 145°, and line 2006 represents the reflectivity in this case.

[0231] With the use of FIG. 13A to FIG. 13DSimilarly, in the case of the resonator of the coil in the open ring, the inter-ring distance at which the reflection becomes zero is set to two distances different from the set distance of 4.5 mm for the flattest matching in the single line. By adjusting the phase shift angle of the wiring connected to the open ring resonator on the power transmission side and the power reception side, two inter-ring distances at which the reflectivity becomes zero can be set, and low reflectivity and high transmittance can be maintained when the distance is between the two distances.

[0232] The above describes the case where the resistance of the power supply is a finite value of 50Ω, which is the same as the impedance of the power transmission line and the power receiving line. In power transmission, in order to achieve high efficiency, it is preferable to use a zero-ohm power supply. When an open-ring resonator is used, as with an LC resonator, a lossless capacitor, inductor, or characteristic impedance line is used to generate the same reactance, thereby coping with the dependence of the reflectivity on the k value.

[0233] First, consider the case where a voltage source with an output impedance of 0Ω is used as a power source so that impedance matching is established, the power source is connected to the input line 1913 via a 100Ω resistor in a single resonator structure, and the power source is connected to the input line 1913 via a 50Ω resistor in a multi-resonator structure. This is a condition for impedance matching to be established in the power source section.

[0234] In the case of a multi-resonator structure, the phase shift angles of the wiring on the power transmission side are 55° and 125°, and the phase shift angles of the wiring on the power reception side are 35° and 145°. Line 2005 represents the transmittance in this case, and line 2006 represents the reflectance in this case. Fig. 20 As described in , for a single resonator structure, when the inter-ring distance is 4.5 mm, the reflectivity becomes 0, and for a multi-resonator structure, when the inter-ring distance is 3.2 mm and 5.6 mm, the reflectivity becomes 0, and impedance matching is established between the power supply and the load.

[0235] Fig.21 21 is a diagram showing the influence of the power supply side line length on the power transmission of a single resonator structure. Line 2101 shows the power consumption of the load, and line 2102 shows the power consumption of the power supply resistance.

[0236] Fig. 22 2201 is a graph showing the influence of the power supply side line length on the power transmission of the multi-resonator structure. Line 2201 shows the power consumption of the load, and line 2202 shows the power consumption of the power supply resistance.

[0237] In both the single resonator structure and the multi-resonator structure, at the inter-loop distance where the reflectivity becomes zero, the power consumption of the load is approximately 25 W, and the power consumption in the power supply resistor is approximately 25 W. Because of the loss in the open loop part, it will not be exactly 25 W.

[0238] As a result, the total power consumption from the power supply, i.e., 50 W, is shared by the power supply resistance and the load part. This means that half of the input power is consumed by the power supply resistance in vain despite the condition of no reflection. In this state, even if the signal line length of the single resonator structure or the line length of the input line 1913 and the output line 1923 in the multi-resonator structure is changed, the transmission power is not affected because there is no reflection anywhere.

[0239] Next, consider Fig. 13B The resonant power transmission circuit 700 uses Fig.19 The capacitor 1331 is a circuit of an open-loop resonator. The capacitance value is a value that makes the impedance value the same as the impedance value of the matching resistor. In the single resonator structure, the capacitance value is 0.65 pF, and in the multi-resonator structure, the capacitance value is 1.3 pF. The capacitor 1331 is provided between the output of the zero-ohm power supply and the branch point 1916 which is the input part of the resonator pair.

[0240] Regarding the single resonator structure, Fig.21 Line 2103 shows the dependence of the power consumption of the load on the inter-ring distance in this case. Regarding the multi-resonator structure, Fig. 22 The line 2203 shows the dependence of the power consumption of the load on the inter-ring distance in this case. It should be noted that the cable length on the power supply side is assumed to be zero.

[0241] Compared with lines 2101 and 2201, which show that both have matching resistors, the load consumes approximately twice the power. This means that the power is consumed by the load without loss. In the case of a multi-resonator structure, the power is approximately constant and is consumed by the load without loss at a ring distance of about 3 mm to 6 mm.

[0242] In the case of microwave circuits, because the wavelength is short, devices are usually connected by impedance lines. In this case, as long as the impedance between the power supply and the resonator, between the resonator and the load, and between the device and the cable is matched, there will be no reflected waves, so even if the cable length changes, there will be no problem. However, if a zero-ohm power supply or a reactance circuit is connected, reflections will be caused between the cable and the power supply, and between the cable and the reactance circuit, which will have an adverse effect on the circuit operation. Therefore, an impedance line is connected as the input line 1913 between the part where the zero-ohm power supply is connected to the capacitor and the branch point 1916 that becomes the input part of the open-loop resonator. Lines 2104 and 2204 represent the power consumption of the load when the length of the impedance line is changed in such a way that the phase shift angle changes between 0° and 360° in 10° increments. Since there is no loss in the input line 1913, the power consumption of the load is the power sent by the power supply.

[0243] For both structures, the power consumption of the load varies depending on the line length, except for the inter-loop distance where the reflectivity becomes zero. In particular, for the single resonator structure, the fluctuation is large when the distance deviates from the distance for achieving impedance matching, so it is necessary to accurately adjust the line length.

[0244] On the other hand, in the case of the multi-resonator structure, the variation between the two inter-loop distances that have been matched is suppressed to a low level. That is, the multi-resonator structure not only transmits constant power over a wide range of inter-loop distances, but also has high tolerance to fluctuations in wiring length. In addition, on the power receiving side, since impedance matching with the load is established, there is no line length dependency of the signal line.

[0245] (Branches with more than three lines)

[0246] In the above description, the case where the line leading to the power supply or load is divided into two is described, but the number is not limited to two. It is also possible to set a wireless power transmission device using more than three resonator pairs. In the case of dividing into three or more lines, a first phase shifting circuit for each line is connected at a branch point, and a resonator pair including a power transmission coil and a power receiving coil is connected to each phase shifting circuit. A second phase shifting circuit is connected to each resonator pair, and each second phase shifting circuit is connected together at a branch point (junction point). In addition, even in the case of dividing into three or more lines, the coupling coefficient of each resonator pair is the same value. Although it is difficult to graphically determine the phase shift angle in the case of dividing into three or more lines as in the case of dividing into two lines, if an optimization program of a circuit simulator is used, the phase shift angle can be determined with high precision.

[0247] Fig.23 Indicates that it is in use Fig.10 , Fig.11 In the case of the SS type resonant power transmission circuit used in the example, when the line is divided into two, three, or four lines, the optimization program is used for each line to obtain the reflection characteristics and transmission characteristics of the phase shift amount of all phase shift circuits on the power transmission side and the power receiving side in a manner that minimizes the reflection within a certain k value range. The range of k values ​​targeted in the optimization and the obtained phase shift angles are shown in Table 3. In the case of two or three lines, the line impedance of a single line is set to 10Ω so that the flattest matching is achieved at k = 0.1. However, in the case of four lines, since a low k value is also important, it is set to 1Ω so that the flattest matching is achieved at k = 0.01.

[0248] [Table 3]

[0249]

[0250] Line 2301 indicates the transmittance in the case of two lines, and line 2304 indicates the reflectance. From line 2301 indicating the transmittance, it can be seen that the range of high efficiency is Fig.11 The range of high efficiency shown by line 1105 is roughly the same and can be adjusted with sufficient accuracy using an optimization program.

[0251] Line 2302 shows the transmittance in the case of three lines, line 2305 shows the reflectance, line 2303 shows the transmittance in the case of four lines, and line 2306 shows the reflectance. It can be seen that as the number of lines increases, the range of high efficiency also increases. It can be seen that although the number of resonators increases as the number of lines increases, and thus the device becomes larger, there are advantages that outweigh this disadvantage.

[0252] In addition, although the case where an LC resonator and an open-loop resonator using a coil are used as the resonator of the resonant power transmission device is described, the resonator is not limited to this. As shown in the example of using an antenna instead of a coil and coupling using an electric field in non-patent document 5, in addition to coils and antennas, the present invention can also be applied to resonators that change the coupling coefficient without changing the resonant frequency when the positional relationship between the resonators changes, so that the reflection becomes zero when equations (4) and (5) are satisfied.

[0253] Although specific examples of the present invention have been described in detail above, these specific examples are merely illustrative and do not limit the claims. The scope of the claims includes specific examples in which various modifications and changes are made to the specific examples described above.

[0254] According to the AC signal transmission device disclosed in the present invention, the change of transmission characteristics caused by the change of coupling coefficient can be suppressed in a wide range, so there is no need for a complex adjustment circuit in contactless power transmission, and a stable contactless power transmission device can be realized using a simple and inexpensive structure. In addition, it can also contribute to the popularization of electric vehicles that need to be charged frequently.

[0255] The disclosure contents of the specification, drawings and abstract contained in Japanese patent application No. 2023-181153 filed on October 20, 2023 are incorporated herein by reference in their entirety.

[0256] Industrial Applicability

[0257] The technology disclosed in the present invention can be used in an AC signal transmission device and an AC device.

Claims

1. An AC signal transmission device, characterized in that: include: Transmission lines; A plurality of first phase shift circuits connected to the transmission line at branch points; a plurality of resonator pairs, respectively connected to the plurality of first phase shift circuits; as well as a plurality of second phase shift circuits, respectively connected to the plurality of resonator pairs, The plurality of second phase shifting circuits are connected to each other at a junction point.

2. The AC signal transmission device according to claim 1, wherein: Even if the coupling state changes, the coupling coefficients of the plurality of resonator pairs are the same value as each other.

3. The AC signal transmission device according to claim 1 or 2, wherein: The resonators constituting each of the plurality of resonator pairs are resonators including a coil and a capacitor.

4. The AC signal transmission device according to claim 1 or 2, wherein: The resonators constituting each of the plurality of resonator pairs are open-ring resonators.

5. The AC signal transmission device according to claim 1, wherein: The transmission line is connected to a zero-ohm power source via a reactive element or an impedance line.

6. The AC signal transmission device according to claim 2, wherein: The phase shift angles of the plurality of first phase shift circuits are set in a manner that matches at least two of the coupling coefficients.

7. An AC device, characterized in that: include: Transmission lines; a plurality of phase shifting circuits connected to the transmission line at branch points; as well as The resonators are respectively connected to the plurality of phase shifting circuits.

8. The AC device according to claim 7, wherein: The resonator is a resonator including a coil and a capacitor.

9. The AC device according to claim 7, wherein: The resonator is a split-ring resonator.

10. The AC device according to claim 7, wherein: Even if the coupling state changes, the coupling coefficients of the resonator pairs formed by the respective resonators of the plurality of resonators have the same value.

11. The AC device according to claim 10, wherein: The phase shift angles of the plurality of phase shift circuits are set in a manner that matches at least two of the coupling coefficients.

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